1. Technical Field
The present invention relates to a circuit for a physical quantity sensor, a physical quantity sensor, and a method for manufacturing the physical quantity sensor.
2. Related Art
There has been a known vibration gyroscope in which a piezoelectric device, such as a quartz vibrator, serves as a gyroscope device.
The vibration gyroscope described in JP-A-2008-107324 includes a piezoelectric device that serves as a gyroscope device, an oscillation circuit that feeds a drive signal back to a drive end of the piezoelectric device to drive and excite the piezoelectric device in such a way that it vibrates, and a drive signal switch circuit that controls output of the drive signal from the oscillation circuit to an external destination, and the drive signal switch circuit outputs drive current or drive voltage of the drive signal from the oscillation circuit as a signal that allows calculation of the series resistance value of the equivalent constant of the piezoelectric device. The series resistance value of the driver of the piezoelectric device is thus measured for a test of the drive level of the piezoelectric device without use of any externally connected measurement apparatus.
The configuration of the vibration gyroscope described in JP-A-2008-107324, however, when the vibration device has a driver and a detector separate from each other, is undesirably not allowed to test the detector.